Rotary underreamer



Patented Mar. 3, 1953 UNITED PATENT OFFICE Ro'r'Aiii" IJNDERRE'AM E it w e lie fliiianuel llionrovi a, ctii'f ,e s'igha te- Oil- Topl- Gompany; Los Angeles; Calif; a corporatioii of California Application iehaer'y 3, 1950',- serieihe. 1 36357 6 chime.- (01. semi)" This invention has to do with ini'firotfr'rfents; rotary oil well undrreafiiers 6f the general type comprising a. body suppertih aplllf li'fiy or out: ters mounted on earners capabl of movement axially and radially or the body as raciany x: panel and contract the cutters; More particu Iai'ly, the invention is directed to the maintenance of the cutter positions ill tools of the type in which the cutters normally or initiallyare' urged toward a contracted position, mm; which and after" the tool has cleared the" casing, the cutters are"expansively'dishlaceable. H

For obvious reasons, it is desirable] to run the 15001 down through the wen easing with the cut-'1 ters' in contracted cdndit'ion, capable'however oi ready expansibility after the underreame pa ses into open hole. As? indicated; umessresh amea by fifieansother than" the-warri g tool itself, the cutters and their carriers l'iav'ben displajceable' during lowering" of the uhderrejamer' so that at times the tool may become obstructed. Accord; ingly, the practice has been tocon'firie thecutters' against expansion by an" eheiren g wireor the like, which is releasable when the tool reaches working position. I

My'prima'ry o'bjct'isto'itfipiovethe'tool'sdthat; by virtue of its structure} and. to theeiiclu'sion of extraneous tying o1" hc' ldingf means, the cutter'sf become releasably confined against exbansion until the cutter carriers are" actuated by opera} tional control of the" tool tdoutwar'dlydisplace the cutters. As" specifically employed, this fea"- ture may' be incorpbra'te'd" a known general typeof underr'earner c'onstrhctioii having the out. ter carriers accommodated fo'i" longitudinal and" radial movement within slots the body; and actuable by downward movement within theslots tdexpand the cutters. It i's' found that hermit-11y; the cutters may'b'e confined against accidental expansion by engaging the'cutter-c'arrier assem'-" bly, and preferably the" top end of the carrieifll against a downwardly" and ontwafdly incliried' body surface, the latterbeing' mast savannageouslylocated at the tori off theceirtitlfrbeii/iiig" body slot. Byyirtue of its .angiila'rityfl' the"inclined body surface-acts to" aisplsbeor'eam the carrier to its radially innefpo'sit'ionl', and to so" retain the carrier untilitfisdisblacedjnresbonse tosiich actuating control as-maybe'e'mployed;

The invention' will'be uhderstoo'd further and b better advantagefrom" the folldviifi g detaile'd de' scr iption ofan" illustrative emhdd'iment showri by" the accompanying drawingjin whichi' v Fig; I is a vie'w showing the-*uriaerreemeh in longitudinal sectionwitE-the'ciitters in -radially contracted pesitionsz 5 Fig, 2 is a siniilai" view showing the cutters ex padd d; a d M 1 Fig 3 is a large scale cross section on line 3-3 of 1.

Referring to the drawings, the tool comprises a tubular body [0 having atits upper end a tubu'-' la'i s lb of coupling l I c'onnectlble' at its pin end 12 with the drill string. The body contains a plurality of lon'gitudina'l slots, l3, typically three, within which are contained the cutter and car-' r ier assemblies. generally indicated at M which are displaceahle vertically within the slots between the Fig. 1 and Fig. 2 pcsitions in' moving the cutters from contractedito their expanded fiositibns. 1 Above the slots; l3 and within a re-- duced section l'5 of its bore, the body contains a cylindrical liner lBjcari'ying one or more key pins ll, the purpose Qf which will later appear. At the lower ends of the'slots the body containsja vertically movable sleevej l8 which is urged upwardly by coil spring I? in a cutter, expanding direction, all as will be presently explained.

s The body [0 contains atubular mandrel 20 having'a'head 2i carrying seal rings 22 and workable yertically within bore 23 of the sub l l. The lower po rt icn of the; mandrel is' exjternally rec'essejsl at2'4- toreceiye the'ke y pin l1, and below the; keyways' the mandrel a relatively elon-' gated and'g'radually'tapered Wed e face 25 termhating at"bbttom wedge surfac e' 25j of relatively great anguIarityL 'Ihen andrelcarries a pilot or circulation conducting pipe 21'" threaded at 28 into the he'ad; of the mandrel andextending downwardlythrough the sleet e18 in engagement with Each of the bo y slots :3 chm-emsa" cutter carrier or holder 30' movableboth' longitudinally and radially within the slot ih responseto rela-' tiyemovernentbetween the carrier and niandrel 20 The carrier" 30 may be of usual general type supporting a pai -of pins 3i and 32 termi ating within the endjpdi tiohshftlie carrier and within a central rib portion 33; Rotatabl cut tersflt are ca'rjrie'clbythe'pihs; Being engaged at-thelower end'sfbyithespring urges sleeve :8;

the utter a 's carr er assemb ies It? are urged upwa-rdlywithhi the'slots l's-a'nd to the limiting (cutterdontractiii) position illustrated ini igf 11 In considering the gehei al mode of ofieraticn' of the underreamer, assume the tool to be'low ered through the casing into the open hole with thetoclparts in the positions illiistrat ed' inFig. 1; After the todl clears the casing fluidcirchla tioxi-dbw'n through" the-drill Caner fl lnandrel 20 "and thebottomhody openings 5 35- is increased force the mandrel and pipe assembly down to the Fig. 2 position and against the resistance of spring l9. Initial engagement of the mandrel face 26 with the inclined cutter carrier surfaces 31 displaces the cutter and carrier assemblies [4 downwardly to the extent of permitting their outward movement within the.slots I3. Thereupon, continued downward movement of the mandrel engages its tapered surface 25 against the carriers, with resultant expansion of the latter to the Fig. 2 positions. Thus during the re maining operation, the cutter carriers are spring urged and supported against the mandrel face 25 and the body shoulders 38 at the upper ends of the slots As previously indicated, in this type of underreamer, the cutter carriers have been confined against outward radial displacement from their are positively actuated for expansion, in this instance by fluid pressure displacement of the mandrel. Such confinement of. the assemblies l4, accomplished by providing the body at the upper ends of the slots I3 with downwardly and outwardly inclined shoulders 46 at the inside of shoulders 38, and which are engageable by the correspondingly inclined faces ll of the cutter carriers. In order that the upper pins 3! may be given full length support within the end portions of the carrier, the pin face may be bevelled at 41 as illustrated.

Thus while the tool is being lowered through the casing the spring thrust of the carrier face 4! against the inclined body shoulder to effectively maintains the cutter and carrier assembly in its innermost radial or contracted position and against unintentional outward displacement. When the tool reaches a location beneath the well casing, circulation fluid is supplied to the tool, to actuate the mandrel downwardly and the cutters outwardly and the tool may then be rotated to perform the desired reaming operation. After the reaming operation has been completed, the circulation fluid pressure is relieved, and the tool is withdrawn upwardly into the casing and from the well. As will be appreciated, the cutters are retracted inwardly during upward movement of the tool by virtue of the engagement of wedge surfaces (H on the cutter pins and carrier with the bottom of the well casing. The resulting wedging action serves to move the cutters inwardly to an extent such that surfaces M are again brought into cutter confining engagement with inclined body shoulders 40. These shoulders will have such angularity, say 45 degrees, as will cause the cutter carriers to be cammed inwardly when engaged against the shoulders under the influence of the coil spring I9.

I claim:

1. In a rotary underreamer, the combination comprising a tubular body having a slot extending through a wall thereof, a cutter, a cutter carrier within said slot in the body and displaceable longitudinally and radially thereof during Accordingly, in order to' expansive and contractive movements of the cutter and carrier, an angular guide surface on the body at one end of the slot and engaged by the carrier toward a corresponding limit of its travel and acting to displace the carrier radially inwardly of the body to cutter contracted position in response to movement of the carrier longitudinally of the body, means for moving the cutter carrier longitudinally of the body against said guide surface to effect said radially inward displacement of the carrier, and a member movable axially relative to said body and having a wedging engagement with said carrier acting upon said axial movement to wedge the carrier radially outwardly. 7

2. In a rotary underreamer, the combination comprising a tubular body having a slot extending through a wall thereof, a cutter, a cutter carrier contained within said longitudinal slot in the body and displaceable therein axially and radially of the body during expansive and" contractive movements of the cutter and carrier, the body having at the upper end of said slot a downwardly and outwardly inclined surface engageable by the carrier and acting to displace the carrier radially inwardly of the body toward the upper limit of the cutter travel to radially contracted position in response to movement of the carrier upwardly within the body, means for elevating the carrier in the slot to engage said inclined surface and eifect said radially inward displacement of the carrier, and a member movable axially relative to said body and having a wedging engagement with said carrier acting upon said axial movement to wedge the carrier radially outwardly against said surface.

3. In a rotary underreamer, the combination comprising a tubular body having'a slot extending through a wall thereof, a cutter, a cutter carrier contained within said longitudinal slot in the body and displaceable therein axially and radially of the body during expansive and contractive movements of the cutter and carrier, said carrier including a pair of outwardly p'r'ojecting end lugs and a cutter pin terminating in said lugs, the body having at and inside thefupper end of said slot an inclined surface engageable by one of said lugs and acting to displace the carrier radially and inwardly of the body toward the upper limit of the cutter travel to radially contracted position in response to movement of the carrier longitudinally of the body, means for elevating the carrier in the slot to engage said inclined surface and effect said radially inward displacement of the carrier, and a member movable axially relative to said body and having a wedging engagement with said carrier acting upon said axial movement to wedge the carrier radially outwardly against said surface to be wedged downwardly thereby against the resistthe top portion of said carrier having a downwardly and outwardly inclined surface, a cutter pin terminating in said portion, the body having at and inside the upper end of said slot a downwardly and outwardly inclined shoulder engageable by said inclined carrier surface toward the "upper limit of the cutter travel to displace the carrier radially and inwardly of the body to contracted position in response to upward movement of the carrier, a spring urging the carrier upwardly, and a mandrel movable axially within said body and having a wedging engagement with said carrier acting to wedge the carrier radially outwardly against said body surface in response to axial movement of the mandrel.

5. In a rotary underreamer, the combination comprising a tubular body having a slot extending through a wall thereof, a cutter, a cutter carrier contained within a longitudinal slot in the body and displaceable therein axially and radially of the body during expansive and contractive movements of the cutter and carrier, the

top portion of said carrier having a downwardly and outwardly inclined surface, a cutter pin terminating in said portion and having a bevelled face inclined in the plane of said inclined carrier surface, the body having at and inside the upper end of said slot a downwardly and outwardly inclined shoulder engageable by said inclined carrier surface toward the upper limit of the cutter travel to displace the carrier radially and inwardly of the body to contracted position in response to upward movement of the carrier, and a spring urging the carrier upwardly.

6. In a rotary underreamer, the combination comprising a tubular body member having a slot extending through a wall thereof, a cutter, a cutter carrier member within said slot in the body member and displaceable axially and ra- 6 dially thereof during expansive and contractive movements of the cutter and carrier member, one of said members having an angular guide surface engaged by a surface of the other member and acting to displace the carrier member radially inwardly of the body to cutter contracted position in response to movement of the carrier member axially of the body, means for moving the carrier member axially of said body member in a direction urging said surfaces of the mem-- bers axially together to effect said radially inward displacement of the carrier member, and a member movable axially relative to said body member and having a wedging engagement with said carrier member acting to wedge the carrier radially outwardly.

VINCENT EMANUEL.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,548,578 Blanchard Aug. 4, 1925 1,804,850 Triplett May 12, 1931 1,819,303 Reed et al. Aug. 18, 1931 1,835,193 Wells Dec. 8, 1931 1,844,358 Grant et al Feb. 9, 1932 2,019,047 Grant Oct. 29, 1935 2,173,018 Hurley Sept. 12, 1939 

